Mice & Rats

Thought to have been originally introduced to the West by ships of early trade merchants and immigrants, the house mouse originated in the arid grasslands of Southeast Asia. Three subspecies similar in appearance are generally referred to under the name of one species, the Mus Musculus. Like their larger counterparts, rats, they are nocturnal creatures, feeding at night to avoid predation. Mice are timid, social, and territorial.

The most common house mouse observed is an ancestor of the white mice used for scientific experimentation. In its wild state, the house mouse is approximately 6.5 inches long including the tail. When found indoors, they can be and usually are considerably larger due to better nutrition. These mice are usually yellowish-gray, sometimes streaked with black. Occasionally, the deer mouse, harvest mouse, and pocket mouse may invade buildings located near fields. When this occurs, they are commonly mistaken with house mice. To distinguish mice from house rats, examine the size of the head and hind feet. Mice have smaller hind feet and heads than young rats.

Biology and Reproduction

In order to implement a truly successful rodent control program, it is important to understand the biology of the pest you want to rid yourself of. When there are good living conditions for the mice, including plenty of food, water, and shelter, they may multiply rapidly. If the opposite is true, living conditions being stressful, population growth is slowed considerably.

After carrying her babies for approximately 19 days, the mother mouse will give birth to anywhere from 4-7 pups per litter. Following 7-10 days of lacking fur, they grow it in and open their eyes and ears. Three to four weeks after birth, the pups are weaned and then begin short trips, starting to explore their surroundings. Although females are technically capable of giving birth approximately every 26 days, they usually produce 8 litters in their lifetime of about 1 year. Female mice are ready to start the cycle of giving birth and mating 5-8 weeks subsequent to their birth.

It is because of these prolific mating habits that mice can quickly become a problem. The potential females have for producing offspring is up to 65-75 if we divide a year by every 28 days in which they can give birth and then multiply that by 5-6 pups per litter.

Behavior

The behavior of mice is often hard to predict, as it is with all rodents and mammals for that matter. However, some generalizations can be made of mice living in and around buildings.

In urban areas, mice may spend their entire lives in buildings. Suburban and rural areas may promote the same kind of complete indoor living as within the city but the mice may live outdoors also. Outdoors, they may live among weeds and shrubbery, near building foundations, in storage sheds, garages, or in the crawl spaces beneath structures. When inside, mice can be found living in their nests, which are almost always close to a food source, in closets, walls, ceiling voids, large appliances, bureaus, the upholstery of furniture, the behind or above the insulation in attics, and in basements.

The nests serve the purpose of providing warmth and protection for female mice when they give birth to their pups. Nests can be made from all sorts of materials including paper, insulation, the stuffing from furniture, or just about any soft material that can be chewed to bits for the purpose of building a nice, soft bed. If the mice nest outside, they will build their homes in ground burrows or among debris.

Once a nest is established and the population grows, the business of territory becomes an important factor. This process of establishing territory is started when a dominant male of the population sets up the area to be controlled. Each territory has a distinct make-up. There is the dominant male mouse as mentioned before along with one or more females, several weak males, and a number of young. When a young mouse leaves the territory, he must fight with the dominant male controlling another territory for control of the one he is in charge of, or search for a yet unclaimed area to set up his own new territory. This is how mouse infestations spread throughout a building.

The size of a territory depends on several different factors. These factors are the physical arrangement of the environment, availability of food and number of mice in the area. Generally, however, a mouse's territory ranges from 10-30 feet. The more food available, the less territory a mouse is bound to have. This is true also of the number of mice occupying an area; the more mice, the less territory. Mice are known not to travel more than a few feet from their nest when food and mice alike are plentiful.

Mice explore and re-explore their territories on a daily basis, becoming extremely familiar with the area. Every pathway to and from water and food becomes ingrained in their little heads along with any burrow entrances and hiding spots from their enemies. Therefore, if any changes occur, they can begin to investigate the alterations and refamiliarize themselves with them.

Treatment

There are many different options for the extermination of rodents. Anticoagulants, snap traps, live catch traps, and glue boards make up a pretty good arsenal for your rodent killing needs. We will discuss all of these options in the section to come as well as variations and subcategories of the treatments.

Anticoagulants: Anticoagulants work basically by disrupting the blood clotting mechanisms in mice, thus causing them to die of internal bleeding. . As with all anticoagulants, death is not immediate and therefore may take up to several days for death to be induced. When using anticoagulants, it is important to keep this in mind if you do not see complete eradiction of a mice colony immediately. This form of extermination is the most widely used and by far the most effective. There are many forms of anticoagulants, the vast majority being baits. In the next section, we will examine the different forms in which they come, bait and otherwise.

Extruded Bait: These types of baits are unsurpassed in palpability, or tastiness, and weatherability. These are optimum for outside baiting needs due to the fact that they retain their effectiveness even when plagued with moisture. They are also excellent for indoor use. Multiple edges make extruded baits very appealing to rodents because they offer multiple edges on which they can gnaw. And, as you know, rodents need to constantly gnaw to keep down the length of their incisor teeth.

Pelleted Baits: Pelleted bait also has a good amount of weatherability so that it may be used outside as well as indoors in moist regions. Palatability and a hard texture for gnawing are another great aspect of this bait, making acceptance by rodents very good. Another aspect that makes this bait unique is its small size. This fact works both for and against it in terms of feasibility for use. On one hand, its small size allows you to place the bait in small, hard to reach areas that may otherwise be inaccessible. Its small size can also be detrimental because one mouse or rat may take it all, bring it back to his nest, and therefore exclude all other different colony members from getting a chance to get a hold of it.

Seed Bait: Seed bait is an excellent form of bait because of the way it imitates a food source that mice already like. Some seed baits are made from canary and millet seed. This is recommended for mice only.

Meal Bait: Meal bait is another palatable form of bait that is useful much in the same way as seed bait, due to the way it imitates what rodents naturally prefer to feed from. Ingredients included in this type of bait are seed and different types of grains to give rodents a variety of textures and flavors. This is the least weatherable of the baits discussed here so it should be used indoors only where the moisture content is not that high.

Liquid Bait: Liquid bait is ideal for use when competition from food source is great or when liquid is unavailable or scarce. This type of bait is ideal for use when exterminating for rats because of the fact that they need a good amount of water on a daily basis. Also, liquid baits may be mixed with water and can be placed in receptacles away from pets or other non-target animals or people. The one drawback is that mice acceptance of the bait is not nearly as high as for rats since mice can live without nearly as much water.

Tracking Powder: Tracking powder is an extremely effective in eradicating rodents. It works by being picked up on the rodent's hair and being consequently ingested when the rodent grooms itself. It is an excellent alternative to bait when bait acceptance is poor. Also, only small amounts of tracking powder are needed and are best put in voided areas that are inaccessible to children and pets.

Glue boards: Glue boards are not a tool that should be used exclusively in the extermination of rodents but they are a great way of getting a colony under control. Glue boards work simply by having a heavy duty piece of cardboard or some other type of material covered in an extremely sticky adhesive glue that is specially formulated to not be affected by dust or other materials that would otherwise hinder the performance of regular glues. Once a mouse or rat steps on it, they are totally stuck. Glue boards come in all different sizes depending on your needs.

Live catch traps: Live catch traps work pretty much how their name sounds. They catch mice and allow them to live so that you may get rid of them in a place far away from your abode. There are single live mouse catch traps and multiple live catch mouse traps. They are best used for monitoring and limiting your current infestation so therefore should not be relied upon for exclusive control measures.

Snap traps: Snap traps are a form of rodent control that just about everyone would first associate with “catching a mouse.” They work by using tension so that when a mouse or rat steps on a certain part of the trap, it snaps shut around their body. There are many variations on the traditional wood and metal version but all guarantee a quick kill.